This invention relates to binders such as ringbinders and the like to used to hold sheets of paper or other material having holes punches in them and, more particularly, to an improved swivel lock assembly for use in such binders.
Certain ringbinders, folders, and similar paper holding or filing units are made with a swivel lock assembly. The assembly includes a locking member having one or more prongs which fit through holes punched along one side of the paper. In these binders, a heavy stock which comprises an outer leaf of the binder is attached to one side of the locking member. A second outer leaf attaches to a slide or locking bar. The slide, in turn, attaches to the other side of the locking member. To open the binder to insert or extract punched material, the slide is first released from the locking member. Next, the respective sides of the locking member are rotated away from each other, this action moving the outer end of the prong, or prongs, away from the side of the member. By releasing the outer end of the prong in this way, the punched material can be removed from the binder, or new material inserted.
Because of the usage to which binders are subjected, the locking member and slide first need to be of a rugged construction. They must also quickly and easily interlock and release from each other to make the insertion or removal of material a simple task. Part of this operation means limiting the degree of movement of the locking member. On the one hand, if the one side of the member cannot move far enough with respect to the other, paper cannot be inserted or removed. On the other hand, if the sides are pulled too far apart, the locking member will not work properly and could be damaged. Present locking member/slide design and construction does not always meet the requirements set forth above, and various improvements would help the performance of the units.